add new emit_inference_failure_err
This commit is contained in:
lcnr
parent
721fc73208
commit
3fe346e7a3
124 changed files with 2113 additions and 629 deletions
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@ -1,21 +1,22 @@
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use crate::infer::type_variable::TypeVariableOriginKind;
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use crate::infer::{InferCtxt, Symbol};
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use rustc_errors::{
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pluralize, struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed,
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};
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use crate::infer::InferCtxt;
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use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticBuilder, ErrorGuaranteed};
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use rustc_hir as hir;
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use rustc_hir::def::{DefKind, Namespace};
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use rustc_hir::def::{CtorOf, DefKind, Namespace};
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use rustc_hir::def_id::DefId;
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use rustc_hir::intravisit::{self, Visitor};
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use rustc_hir::{Body, Expr, ExprKind, FnRetTy, HirId, Local, MatchSource, Pat};
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use rustc_hir::{Body, Expr, ExprKind, FnRetTy, HirId, Local, LocalSource};
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use rustc_middle::hir::nested_filter;
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use rustc_middle::infer::unify_key::ConstVariableOriginKind;
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use rustc_middle::ty::print::Print;
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use rustc_middle::ty::subst::{GenericArg, GenericArgKind};
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use rustc_middle::ty::{self, Const, DefIdTree, InferConst, Ty, TyCtxt, TypeFoldable, TypeFolder};
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use rustc_span::symbol::kw;
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use rustc_span::{sym, Span};
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use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMutability};
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use rustc_middle::ty::print::{FmtPrinter, PrettyPrinter, Print, Printer};
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use rustc_middle::ty::subst::{GenericArg, GenericArgKind, Subst, SubstsRef};
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use rustc_middle::ty::{self, DefIdTree, GenericParamDefKind, InferConst};
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use rustc_middle::ty::{Ty, TyCtxt};
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use rustc_span::symbol::{kw, Ident};
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use rustc_span::{BytePos, Span};
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use std::borrow::Cow;
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use std::iter;
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pub enum TypeAnnotationNeeded {
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/// ```compile_fail,E0282
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@ -54,9 +55,8 @@ pub struct InferenceDiagnosticsData {
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/// Data on the parent definition where a generic argument was declared.
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pub struct InferenceDiagnosticsParentData {
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pub prefix: &'static str,
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pub name: String,
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pub def_id: DefId,
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prefix: &'static str,
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name: String,
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}
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pub enum UnderspecifiedArgKind {
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@ -81,6 +81,18 @@ impl InferenceDiagnosticsData {
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// For example: "cannot infer type for type parameter `T`"
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format!("cannot infer {} `{}`{}", self.kind.prefix_string(), self.name, suffix)
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}
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fn where_x_is_specified(&self, in_type: Ty<'_>) -> String {
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if in_type.is_ty_infer() {
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String::new()
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} else if self.name == "_" {
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// FIXME: Consider specializing this message if there is a single `_`
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// in the type.
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", where the placeholders `_` are specified".to_string()
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} else {
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format!(", where the {} `{}` is specified", self.kind.prefix_string(), self.name)
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}
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}
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}
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impl InferenceDiagnosticsParentData {
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@ -94,7 +106,6 @@ impl InferenceDiagnosticsParentData {
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Some(InferenceDiagnosticsParentData {
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prefix: tcx.def_kind(parent_def_id).descr(parent_def_id),
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name: parent_name,
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def_id: parent_def_id,
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})
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}
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@ -117,6 +128,80 @@ impl UnderspecifiedArgKind {
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}
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}
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fn fmt_printer<'a, 'tcx>(infcx: &'a InferCtxt<'_, 'tcx>, ns: Namespace) -> FmtPrinter<'a, 'tcx> {
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let mut printer = FmtPrinter::new(infcx.tcx, ns);
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let ty_getter = move |ty_vid| {
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if infcx.probe_ty_var(ty_vid).is_ok() {
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warn!("resolved ty var in error message");
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}
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if let TypeVariableOriginKind::TypeParameterDefinition(name, _) =
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infcx.inner.borrow_mut().type_variables().var_origin(ty_vid).kind
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{
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Some(name.to_string())
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} else {
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None
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}
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};
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printer.ty_infer_name_resolver = Some(Box::new(ty_getter));
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let const_getter = move |ct_vid| {
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if infcx.probe_const_var(ct_vid).is_ok() {
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warn!("resolved const var in error message");
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}
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if let ConstVariableOriginKind::ConstParameterDefinition(name, _) =
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infcx.inner.borrow_mut().const_unification_table().probe_value(ct_vid).origin.kind
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{
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return Some(name.to_string());
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} else {
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None
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}
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};
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printer.const_infer_name_resolver = Some(Box::new(const_getter));
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printer
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}
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fn ty_to_string<'tcx>(infcx: &InferCtxt<'_, 'tcx>, ty: Ty<'tcx>) -> String {
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let printer = fmt_printer(infcx, Namespace::TypeNS);
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let ty = infcx.resolve_vars_if_possible(ty);
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match ty.kind() {
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// We don't want the regular output for `fn`s because it includes its path in
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// invalid pseudo-syntax, we want the `fn`-pointer output instead.
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ty::FnDef(..) => ty.fn_sig(infcx.tcx).print(printer).unwrap().into_buffer(),
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// FIXME: The same thing for closures, but this only works when the closure
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// does not capture anything.
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//
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// We do have to hide the `extern "rust-call"` ABI in that case though,
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// which is too much of a bother for now.
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_ => ty.print(printer).unwrap().into_buffer(),
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}
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}
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/// We don't want to directly use `ty_to_string` for closures as their type isn't really
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/// something users are familar with. Directly printing the `fn_sig` of closures also
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/// doesn't work as they actually use the "rust-call" API.
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fn closure_as_fn_str<'tcx>(infcx: &InferCtxt<'_, 'tcx>, ty: Ty<'tcx>) -> String {
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let ty::Closure(_, substs) = ty.kind() else { unreachable!() };
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let fn_sig = substs.as_closure().sig();
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let args = fn_sig
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.inputs()
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.skip_binder()
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.iter()
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.next()
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.map(|args| {
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args.tuple_fields()
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.iter()
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.map(|arg| ty_to_string(infcx, arg))
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.collect::<Vec<_>>()
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.join(", ")
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})
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.unwrap_or_default();
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let ret = if fn_sig.output().skip_binder().is_unit() {
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String::new()
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} else {
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format!(" -> {}", ty_to_string(infcx, fn_sig.output().skip_binder()))
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};
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format!("fn({}){}", args, ret)
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}
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impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
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/// Extracts data used by diagnostic for either types or constants
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/// which were stuck during inference.
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@ -153,9 +238,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
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if let Some(highlight) = highlight {
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printer.region_highlight_mode = highlight;
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}
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let name = ty.print(printer).unwrap().into_buffer();
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InferenceDiagnosticsData {
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name,
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name: ty.print(printer).unwrap().into_buffer(),
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span: None,
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kind: UnderspecifiedArgKind::Type { prefix: ty.prefix_string(self.tcx) },
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parent: None,
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@ -177,8 +261,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
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}
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debug_assert!(!origin.span.is_dummy());
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let mut printer =
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ty::print::FmtPrinter::new(self.tcx, Namespace::ValueNS);
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let mut printer = ty::print::FmtPrinter::new(self.tcx, Namespace::ValueNS);
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if let Some(highlight) = highlight {
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printer.region_highlight_mode = highlight;
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}
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@ -189,7 +272,17 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
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parent: None,
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}
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} else {
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bug!("unexpect const: {:?}", ct);
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// FIXME: This code seems a bit wrong, idk.
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let mut printer = ty::print::FmtPrinter::new(self.tcx, Namespace::ValueNS);
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if let Some(highlight) = highlight {
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printer.region_highlight_mode = highlight;
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}
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InferenceDiagnosticsData {
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name: ct.print(printer).unwrap().into_buffer(),
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span: None,
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kind: UnderspecifiedArgKind::Const { is_parameter: false },
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parent: None,
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}
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}
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}
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GenericArgKind::Lifetime(_) => bug!("unexpected lifetime"),
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@ -201,17 +294,160 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
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body_id: Option<hir::BodyId>,
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span: Span,
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arg: GenericArg<'tcx>,
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impl_candidates: Vec<ty::TraitRef<'tcx>>,
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// FIXME(#94483): Either use this or remove it.
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_impl_candidates: Vec<ty::TraitRef<'tcx>>,
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error_code: TypeAnnotationNeeded,
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) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
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let arg = self.resolve_vars_if_possible(arg);
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let arg_data = self.extract_inference_diagnostics_data(arg, None);
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let mut local_visitor = FindInferSourceVisitor::new(&self, arg);
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if let Some(body_id) = body_id {
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let expr = self.tcx.hir().expect_expr(body_id.hir_id);
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debug!(?expr);
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local_visitor.visit_expr(expr);
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}
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let Some(InferSource { span, kind }) = local_visitor.infer_source else {
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let error_code = error_code.into();
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let mut err = self.tcx.sess.struct_span_err_with_code(
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span,
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&format!("type annotations needed"),
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error_code,
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);
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err.span_label(
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span,
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arg_data.cannot_infer_msg(),
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);
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return err;
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};
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let error_code = error_code.into();
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let err = self.tcx.sess.struct_span_err_with_code(
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let mut err = self.tcx.sess.struct_span_err_with_code(
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span,
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&format!("type annotations needed"),
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&format!("type annotations needed{}", kind.ty_msg(self)),
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error_code,
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);
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match kind {
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InferSourceKind::LetBinding { insert_span, pattern_name, ty } => {
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let suggestion_msg = if let Some(name) = pattern_name {
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format!(
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"consider giving `{}` an explicit type{}",
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name,
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arg_data.where_x_is_specified(ty)
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)
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} else {
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format!(
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"consider giving this pattern a type{}",
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arg_data.where_x_is_specified(ty)
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)
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};
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err.span_suggestion_verbose(
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insert_span,
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&suggestion_msg,
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format!(": {}", ty_to_string(self, ty)),
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Applicability::HasPlaceholders,
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);
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}
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InferSourceKind::ClosureArg { insert_span, ty } => {
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err.span_suggestion_verbose(
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insert_span,
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&format!(
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"consider giving this closure parameter an explicit type{}",
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arg_data.where_x_is_specified(ty)
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),
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format!(": {}", ty_to_string(self, ty)),
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Applicability::HasPlaceholders,
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);
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}
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InferSourceKind::GenericArg {
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insert_span,
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argument_index,
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generics_def_id,
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def_id: _,
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generic_args,
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} => {
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let generics = self.tcx.generics_of(generics_def_id);
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let is_type = matches!(arg.unpack(), GenericArgKind::Type(_));
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let cannot_infer_msg = format!(
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"cannot infer {} of the {} parameter `{}`{}",
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if is_type { "type" } else { "the value" },
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if is_type { "type" } else { "const" },
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generics.params[argument_index].name,
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// We use the `generics_def_id` here, as even when suggesting `None::<T>`,
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// the type parameter `T` was still declared on the enum, not on the
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// variant.
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InferenceDiagnosticsParentData::for_parent_def_id(self.tcx, generics_def_id)
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.map_or(String::new(), |parent| parent.suffix_string()),
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);
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err.span_label(span, cannot_infer_msg);
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let printer = fmt_printer(self, Namespace::TypeNS);
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let args = printer.comma_sep(generic_args.iter().copied()).unwrap().into_buffer();
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err.span_suggestion_verbose(
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insert_span,
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&format!("consider specifying the generic argument{}", pluralize!(args.len()),),
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format!("::<{}>", args),
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Applicability::HasPlaceholders,
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);
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}
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InferSourceKind::FullyQualifiedMethodCall { receiver, successor, substs, def_id } => {
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let typeck_results = self.in_progress_typeck_results.unwrap();
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let typeck_results = typeck_results.borrow();
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let printer = fmt_printer(self, Namespace::ValueNS);
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let def_path = printer.print_def_path(def_id, substs).unwrap().into_buffer();
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// We only care about whether we have to add `&` or `&mut ` for now.
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// This is the case if the last adjustment is a borrow and the
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// first adjustment was not a builtin deref.
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let adjustment = match typeck_results.expr_adjustments(receiver) {
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[
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Adjustment { kind: Adjust::Deref(None), target: _ },
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..,
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Adjustment { kind: Adjust::Borrow(AutoBorrow::Ref(..)), target: _ },
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] => "",
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[
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..,
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Adjustment { kind: Adjust::Borrow(AutoBorrow::Ref(_, mut_)), target: _ },
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] => match mut_ {
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AutoBorrowMutability::Mut { .. } => "&mut ",
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AutoBorrowMutability::Not => "&",
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},
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_ => "",
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};
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let suggestion = vec![
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(receiver.span.shrink_to_lo(), format!("{def_path}({adjustment}")),
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(receiver.span.shrink_to_hi().with_hi(successor.1), successor.0.to_string()),
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];
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err.multipart_suggestion(
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"try using a fully qualified path to specify the expected types",
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suggestion,
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Applicability::HasPlaceholders,
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);
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}
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InferSourceKind::ClosureReturn { ty, data, should_wrap_expr } => {
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let ret = ty_to_string(self, ty);
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let (arrow, post) = match data {
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FnRetTy::DefaultReturn(_) => ("-> ", " "),
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_ => ("", ""),
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};
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let suggestion = match should_wrap_expr {
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Some(end_span) => vec![
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(data.span(), format!("{}{}{}{{ ", arrow, ret, post)),
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(end_span, " }".to_string()),
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],
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None => vec![(data.span(), format!("{}{}{}", arrow, ret, post))],
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};
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err.multipart_suggestion(
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"try giving this closure an explicit return type",
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suggestion,
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Applicability::HasPlaceholders,
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);
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}
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}
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err
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}
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@ -235,3 +471,550 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
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err
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}
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}
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#[derive(Debug)]
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struct InferSource<'tcx> {
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span: Span,
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kind: InferSourceKind<'tcx>,
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}
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#[derive(Debug)]
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enum InferSourceKind<'tcx> {
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LetBinding {
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insert_span: Span,
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pattern_name: Option<Ident>,
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ty: Ty<'tcx>,
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},
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ClosureArg {
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insert_span: Span,
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ty: Ty<'tcx>,
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},
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GenericArg {
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insert_span: Span,
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argument_index: usize,
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generics_def_id: DefId,
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def_id: DefId,
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generic_args: &'tcx [GenericArg<'tcx>],
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},
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FullyQualifiedMethodCall {
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receiver: &'tcx Expr<'tcx>,
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/// If the method has other arguments, this is ", " and the start of the first argument,
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/// while for methods without arguments this is ")" and the end of the method call.
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successor: (&'static str, BytePos),
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substs: SubstsRef<'tcx>,
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def_id: DefId,
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},
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ClosureReturn {
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ty: Ty<'tcx>,
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data: &'tcx FnRetTy<'tcx>,
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should_wrap_expr: Option<Span>,
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},
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}
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impl<'tcx> InferSourceKind<'tcx> {
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fn ty_msg(&self, infcx: &InferCtxt<'_, 'tcx>) -> String {
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match *self {
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InferSourceKind::LetBinding { ty, .. }
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| InferSourceKind::ClosureArg { ty, .. }
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| InferSourceKind::ClosureReturn { ty, .. } => {
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if ty.is_closure() {
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format!(" for the closure `{}`", closure_as_fn_str(infcx, ty))
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} else if !ty.is_ty_infer() {
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format!(" for `{}`", ty_to_string(infcx, ty))
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} else {
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String::new()
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}
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}
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// FIXME: We should be able to add some additional info here.
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InferSourceKind::GenericArg { .. }
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| InferSourceKind::FullyQualifiedMethodCall { .. } => String::new(),
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}
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}
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}
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struct InsertableGenericArgs<'tcx> {
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insert_span: Span,
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substs: SubstsRef<'tcx>,
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generics_def_id: DefId,
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def_id: DefId,
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}
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||||
|
||||
/// A visitor which searches for the "best" spot to use in the inference error.
|
||||
///
|
||||
/// For this it walks over the hir body and tries to check all places where
|
||||
/// inference variables could be bound.
|
||||
///
|
||||
/// While doing so, the currently best spot is stored in `infer_source`.
|
||||
/// For details on how we rank spots, see [Self::source_cost]
|
||||
struct FindInferSourceVisitor<'a, 'tcx> {
|
||||
infcx: &'a InferCtxt<'a, 'tcx>,
|
||||
target: GenericArg<'tcx>,
|
||||
|
||||
attempt: usize,
|
||||
infer_source_cost: usize,
|
||||
infer_source: Option<InferSource<'tcx>>,
|
||||
}
|
||||
|
||||
impl<'a, 'tcx> FindInferSourceVisitor<'a, 'tcx> {
|
||||
fn new(infcx: &'a InferCtxt<'a, 'tcx>, target: GenericArg<'tcx>) -> Self {
|
||||
FindInferSourceVisitor {
|
||||
infcx,
|
||||
target,
|
||||
|
||||
attempt: 0,
|
||||
infer_source_cost: usize::MAX,
|
||||
infer_source: None,
|
||||
}
|
||||
}
|
||||
|
||||
/// Computes cost for the given source.
|
||||
///
|
||||
/// Sources with a small cost are prefer and should result
|
||||
/// in a clearer and idiomatic suggestion.
|
||||
fn source_cost(&self, source: &InferSource<'tcx>) -> usize {
|
||||
let tcx = self.infcx.tcx;
|
||||
|
||||
fn arg_cost<'tcx>(arg: GenericArg<'tcx>) -> usize {
|
||||
match arg.unpack() {
|
||||
GenericArgKind::Lifetime(_) => 0, // erased
|
||||
GenericArgKind::Type(ty) => ty_cost(ty),
|
||||
GenericArgKind::Const(_) => 3, // some non-zero value
|
||||
}
|
||||
}
|
||||
fn ty_cost<'tcx>(ty: Ty<'tcx>) -> usize {
|
||||
match ty.kind() {
|
||||
ty::Closure(..) => 100,
|
||||
ty::FnDef(..) => 20,
|
||||
ty::FnPtr(..) => 10,
|
||||
ty::Infer(..) => 0,
|
||||
_ => 1,
|
||||
}
|
||||
}
|
||||
|
||||
// The sources are listed in order of preference here.
|
||||
match source.kind {
|
||||
InferSourceKind::LetBinding { ty, .. } => ty_cost(ty),
|
||||
InferSourceKind::ClosureArg { ty, .. } => 5 + ty_cost(ty),
|
||||
InferSourceKind::GenericArg { def_id, generic_args, .. } => {
|
||||
let variant_cost = match tcx.def_kind(def_id) {
|
||||
DefKind::Variant | DefKind::Ctor(CtorOf::Variant, _) => 15, // `None::<u32>` and friends are ugly.
|
||||
_ => 12,
|
||||
};
|
||||
variant_cost + generic_args.iter().map(|&arg| arg_cost(arg)).sum::<usize>()
|
||||
}
|
||||
InferSourceKind::FullyQualifiedMethodCall { substs, .. } => {
|
||||
// FIXME: We should also consider the cost of lifetimes and constants here.
|
||||
20 + substs.iter().map(|arg| arg_cost(arg)).sum::<usize>()
|
||||
}
|
||||
InferSourceKind::ClosureReturn { ty, should_wrap_expr, .. } => {
|
||||
30 + ty_cost(ty) + if should_wrap_expr.is_some() { 10 } else { 0 }
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// Uses `fn source_cost` to determine whether this inference source is preferable to
|
||||
/// previous sources. We generally prefer earlier sources.
|
||||
#[instrument(level = "debug", skip(self))]
|
||||
fn update_infer_source(&mut self, new_source: InferSource<'tcx>) {
|
||||
let cost = self.source_cost(&new_source) + self.attempt;
|
||||
self.attempt += 1;
|
||||
if cost < self.infer_source_cost {
|
||||
self.infer_source_cost = cost;
|
||||
self.infer_source = Some(new_source);
|
||||
}
|
||||
}
|
||||
|
||||
fn opt_node_type(&self, hir_id: HirId) -> Option<Ty<'tcx>> {
|
||||
let ty = self.infcx.in_progress_typeck_results?.borrow().node_type_opt(hir_id);
|
||||
self.infcx.resolve_vars_if_possible(ty)
|
||||
}
|
||||
|
||||
// Check whether this generic argument is the inference variable we
|
||||
// are looking for.
|
||||
fn generic_arg_is_target(&self, arg: GenericArg<'tcx>) -> bool {
|
||||
if arg == self.target {
|
||||
return true;
|
||||
}
|
||||
|
||||
match (arg.unpack(), self.target.unpack()) {
|
||||
(GenericArgKind::Type(inner_ty), GenericArgKind::Type(target_ty)) => {
|
||||
use ty::{Infer, TyVar};
|
||||
match (inner_ty.kind(), target_ty.kind()) {
|
||||
(&Infer(TyVar(a_vid)), &Infer(TyVar(b_vid))) => {
|
||||
self.infcx.inner.borrow_mut().type_variables().sub_unified(a_vid, b_vid)
|
||||
}
|
||||
_ => false,
|
||||
}
|
||||
}
|
||||
(GenericArgKind::Const(inner_ct), GenericArgKind::Const(target_ct)) => {
|
||||
use ty::InferConst::*;
|
||||
match (inner_ct.val(), target_ct.val()) {
|
||||
(ty::ConstKind::Infer(Var(a_vid)), ty::ConstKind::Infer(Var(b_vid))) => self
|
||||
.infcx
|
||||
.inner
|
||||
.borrow_mut()
|
||||
.const_unification_table()
|
||||
.unioned(a_vid, b_vid),
|
||||
_ => false,
|
||||
}
|
||||
}
|
||||
_ => false,
|
||||
}
|
||||
}
|
||||
|
||||
/// Does this generic argument contain our target inference variable
|
||||
/// in a way which can be written by the user.
|
||||
fn generic_arg_contains_target(&self, arg: GenericArg<'tcx>) -> bool {
|
||||
let mut walker = arg.walk();
|
||||
while let Some(inner) = walker.next() {
|
||||
if self.generic_arg_is_target(inner) {
|
||||
return true;
|
||||
}
|
||||
match inner.unpack() {
|
||||
GenericArgKind::Lifetime(_) => {}
|
||||
GenericArgKind::Type(ty) => {
|
||||
if matches!(ty.kind(), ty::Opaque(..)) {
|
||||
// Opaque types can't be named by the user right now
|
||||
// FIXME(type_alias_impl_trait): These opaque types
|
||||
// can actually be named, so it would make sense to
|
||||
// adjust this case and add a test for it.
|
||||
walker.skip_current_subtree();
|
||||
}
|
||||
}
|
||||
GenericArgKind::Const(ct) => {
|
||||
if matches!(ct.val(), ty::ConstKind::Unevaluated(..)) {
|
||||
// You can't write the generic arguments for
|
||||
// unevaluated constants.
|
||||
walker.skip_current_subtree();
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
false
|
||||
}
|
||||
|
||||
fn expr_inferred_subst_iter(
|
||||
&self,
|
||||
expr: &'tcx hir::Expr<'tcx>,
|
||||
) -> Box<dyn Iterator<Item = InsertableGenericArgs<'tcx>> + 'a> {
|
||||
let tcx = self.infcx.tcx;
|
||||
let typeck_results = self.infcx.in_progress_typeck_results.unwrap().borrow();
|
||||
match expr.kind {
|
||||
hir::ExprKind::Path(ref path) => {
|
||||
if let Some(substs) = typeck_results.node_substs_opt(expr.hir_id) {
|
||||
return self.path_inferred_subst_iter(expr.hir_id, substs, path);
|
||||
}
|
||||
}
|
||||
hir::ExprKind::Struct(path, _, _) => {
|
||||
if let Some(ty) = self.opt_node_type(expr.hir_id) {
|
||||
if let ty::Adt(_, substs) = ty.kind() {
|
||||
return self.path_inferred_subst_iter(expr.hir_id, substs, path);
|
||||
}
|
||||
}
|
||||
}
|
||||
hir::ExprKind::MethodCall(segment, _, _) => {
|
||||
if let Some(def_id) = typeck_results.type_dependent_def_id(expr.hir_id) {
|
||||
let generics = tcx.generics_of(def_id);
|
||||
let insertable: Option<_> = try {
|
||||
if generics.has_impl_trait() {
|
||||
None?
|
||||
}
|
||||
let substs = typeck_results.node_substs_opt(expr.hir_id)?;
|
||||
let span = tcx.hir().span(segment.hir_id?);
|
||||
let insert_span = segment.ident.span.shrink_to_hi().with_hi(span.hi());
|
||||
InsertableGenericArgs {
|
||||
insert_span,
|
||||
substs,
|
||||
generics_def_id: def_id,
|
||||
def_id,
|
||||
}
|
||||
};
|
||||
return Box::new(insertable.into_iter());
|
||||
}
|
||||
}
|
||||
_ => {}
|
||||
}
|
||||
|
||||
Box::new(iter::empty())
|
||||
}
|
||||
|
||||
fn resolved_path_inferred_subst_iter(
|
||||
&self,
|
||||
path: &'tcx hir::Path<'tcx>,
|
||||
substs: SubstsRef<'tcx>,
|
||||
) -> impl Iterator<Item = InsertableGenericArgs<'tcx>> + 'a {
|
||||
let tcx = self.infcx.tcx;
|
||||
// The last segment of a path often has `Res::Err` and the
|
||||
// correct `Res` is the one of the whole path.
|
||||
//
|
||||
// FIXME: We deal with that one separately for now,
|
||||
// would be good to remove this special case.
|
||||
let last_segment_using_path_data: Option<_> = try {
|
||||
let generics_def_id = tcx.res_generics_def_id(path.res)?;
|
||||
let generics = tcx.generics_of(generics_def_id);
|
||||
if generics.has_impl_trait() {
|
||||
None?
|
||||
}
|
||||
let insert_span =
|
||||
path.segments.last().unwrap().ident.span.shrink_to_hi().with_hi(path.span.hi());
|
||||
InsertableGenericArgs {
|
||||
insert_span,
|
||||
substs,
|
||||
generics_def_id,
|
||||
def_id: path.res.def_id(),
|
||||
}
|
||||
};
|
||||
|
||||
path.segments
|
||||
.iter()
|
||||
.filter_map(move |segment| {
|
||||
let res = segment.res?;
|
||||
let generics_def_id = tcx.res_generics_def_id(res)?;
|
||||
let generics = tcx.generics_of(generics_def_id);
|
||||
if generics.has_impl_trait() {
|
||||
return None;
|
||||
}
|
||||
let span = tcx.hir().span(segment.hir_id?);
|
||||
let insert_span = segment.ident.span.shrink_to_hi().with_hi(span.hi());
|
||||
Some(InsertableGenericArgs {
|
||||
insert_span,
|
||||
substs,
|
||||
generics_def_id,
|
||||
def_id: res.def_id(),
|
||||
})
|
||||
})
|
||||
.chain(last_segment_using_path_data)
|
||||
}
|
||||
|
||||
fn path_inferred_subst_iter(
|
||||
&self,
|
||||
hir_id: HirId,
|
||||
substs: SubstsRef<'tcx>,
|
||||
qpath: &'tcx hir::QPath<'tcx>,
|
||||
) -> Box<dyn Iterator<Item = InsertableGenericArgs<'tcx>> + 'a> {
|
||||
let tcx = self.infcx.tcx;
|
||||
let typeck_results = self.infcx.in_progress_typeck_results.unwrap().borrow();
|
||||
match qpath {
|
||||
hir::QPath::Resolved(_self_ty, path) => {
|
||||
Box::new(self.resolved_path_inferred_subst_iter(path, substs))
|
||||
}
|
||||
hir::QPath::TypeRelative(ty, segment) => {
|
||||
let Some(def_id) = typeck_results.type_dependent_def_id(hir_id) else {
|
||||
return Box::new(iter::empty());
|
||||
};
|
||||
|
||||
let generics = tcx.generics_of(def_id);
|
||||
let segment: Option<_> = try {
|
||||
if !segment.infer_args || generics.has_impl_trait() {
|
||||
None?;
|
||||
}
|
||||
let span = tcx.hir().span(segment.hir_id?);
|
||||
let insert_span = segment.ident.span.shrink_to_hi().with_hi(span.hi());
|
||||
InsertableGenericArgs { insert_span, substs, generics_def_id: def_id, def_id }
|
||||
};
|
||||
|
||||
let parent_def_id = generics.parent.unwrap();
|
||||
if tcx.def_kind(parent_def_id) == DefKind::Impl {
|
||||
let parent_ty = tcx.bound_type_of(parent_def_id).subst(tcx, substs);
|
||||
match (parent_ty.kind(), &ty.kind) {
|
||||
(
|
||||
ty::Adt(def, substs),
|
||||
hir::TyKind::Path(hir::QPath::Resolved(_self_ty, path)),
|
||||
) => {
|
||||
if tcx.res_generics_def_id(path.res) != Some(def.did()) {
|
||||
bug!(
|
||||
"unexpected path: def={:?} substs={:?} path={:?}",
|
||||
def,
|
||||
substs,
|
||||
path,
|
||||
);
|
||||
} else {
|
||||
return Box::new(
|
||||
self.resolved_path_inferred_subst_iter(path, substs)
|
||||
.chain(segment),
|
||||
);
|
||||
}
|
||||
}
|
||||
_ => (),
|
||||
}
|
||||
}
|
||||
|
||||
Box::new(segment.into_iter())
|
||||
}
|
||||
hir::QPath::LangItem(_, _, _) => Box::new(iter::empty()),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
impl<'a, 'tcx> Visitor<'tcx> for FindInferSourceVisitor<'a, 'tcx> {
|
||||
type NestedFilter = nested_filter::OnlyBodies;
|
||||
|
||||
fn nested_visit_map(&mut self) -> Self::Map {
|
||||
self.infcx.tcx.hir()
|
||||
}
|
||||
|
||||
fn visit_local(&mut self, local: &'tcx Local<'tcx>) {
|
||||
intravisit::walk_local(self, local);
|
||||
|
||||
if let Some(ty) = self.opt_node_type(local.hir_id) {
|
||||
if self.generic_arg_contains_target(ty.into()) {
|
||||
match local.source {
|
||||
LocalSource::Normal if local.ty.is_none() => {
|
||||
self.update_infer_source(InferSource {
|
||||
span: local.pat.span,
|
||||
kind: InferSourceKind::LetBinding {
|
||||
insert_span: local.pat.span.shrink_to_hi(),
|
||||
pattern_name: local.pat.simple_ident(),
|
||||
ty,
|
||||
},
|
||||
})
|
||||
}
|
||||
_ => {}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/// For closures, we first visit the parameters and then the content,
|
||||
/// as we prefer those.
|
||||
fn visit_body(&mut self, body: &'tcx Body<'tcx>) {
|
||||
for param in body.params {
|
||||
debug!(
|
||||
"param: span {:?}, ty_span {:?}, pat.span {:?}",
|
||||
param.span, param.ty_span, param.pat.span
|
||||
);
|
||||
if param.ty_span != param.pat.span {
|
||||
debug!("skipping param: has explicit type");
|
||||
continue;
|
||||
}
|
||||
|
||||
let Some(param_ty) = self.opt_node_type(param.hir_id) else {
|
||||
continue
|
||||
};
|
||||
|
||||
if self.generic_arg_contains_target(param_ty.into()) {
|
||||
self.update_infer_source(InferSource {
|
||||
span: param.pat.span,
|
||||
kind: InferSourceKind::ClosureArg {
|
||||
insert_span: param.pat.span.shrink_to_hi(),
|
||||
ty: param_ty,
|
||||
},
|
||||
})
|
||||
}
|
||||
}
|
||||
intravisit::walk_body(self, body);
|
||||
}
|
||||
|
||||
fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) {
|
||||
let tcx = self.infcx.tcx;
|
||||
match expr.kind {
|
||||
// When encountering `func(arg)` first look into `arg` and then `func`,
|
||||
// as `arg` is "more specific".
|
||||
ExprKind::Call(func, args) => {
|
||||
for arg in args {
|
||||
self.visit_expr(arg);
|
||||
}
|
||||
self.visit_expr(func);
|
||||
}
|
||||
_ => intravisit::walk_expr(self, expr),
|
||||
}
|
||||
|
||||
for InsertableGenericArgs { insert_span, substs, generics_def_id, def_id } in
|
||||
self.expr_inferred_subst_iter(expr)
|
||||
{
|
||||
let generics = tcx.generics_of(generics_def_id);
|
||||
if let Some(argument_index) =
|
||||
generics.own_substs(substs).iter().position(|&arg| self.generic_arg_is_target(arg))
|
||||
{
|
||||
let substs = self.infcx.resolve_vars_if_possible(substs);
|
||||
let num_args = generics
|
||||
.params
|
||||
.iter()
|
||||
.rev()
|
||||
.filter(|&p| !matches!(p.kind, GenericParamDefKind::Lifetime))
|
||||
.skip_while(|¶m| {
|
||||
if let Some(default) = param.default_value(tcx) {
|
||||
// FIXME: Using structural comparisions has a bunch of false negatives.
|
||||
//
|
||||
// We should instead try to replace inference variables with placeholders and
|
||||
// then use `infcx.can_eq`. That probably should be a separate method
|
||||
// generally used during error reporting.
|
||||
default.subst(tcx, substs) == substs[param.index as usize]
|
||||
} else {
|
||||
false
|
||||
}
|
||||
})
|
||||
.count();
|
||||
let generic_args =
|
||||
&generics.own_substs(substs)[generics.own_counts().lifetimes..][..num_args];
|
||||
let span = match expr.kind {
|
||||
ExprKind::MethodCall(path, _, _) => path.ident.span,
|
||||
_ => expr.span,
|
||||
};
|
||||
|
||||
self.update_infer_source(InferSource {
|
||||
span,
|
||||
kind: InferSourceKind::GenericArg {
|
||||
insert_span,
|
||||
argument_index,
|
||||
generics_def_id,
|
||||
def_id,
|
||||
generic_args,
|
||||
},
|
||||
});
|
||||
}
|
||||
}
|
||||
|
||||
if let Some(node_ty) = self.opt_node_type(expr.hir_id) {
|
||||
if let (&ExprKind::Closure(_, decl, body_id, span, _), ty::Closure(_, substs)) =
|
||||
(&expr.kind, node_ty.kind())
|
||||
{
|
||||
let output = substs.as_closure().sig().output().skip_binder();
|
||||
if self.generic_arg_contains_target(output.into()) {
|
||||
let body = self.infcx.tcx.hir().body(body_id);
|
||||
let should_wrap_expr = if matches!(body.value.kind, ExprKind::Block(..)) {
|
||||
None
|
||||
} else {
|
||||
Some(body.value.span.shrink_to_hi())
|
||||
};
|
||||
self.update_infer_source(InferSource {
|
||||
span,
|
||||
kind: InferSourceKind::ClosureReturn {
|
||||
ty: output,
|
||||
data: &decl.output,
|
||||
should_wrap_expr,
|
||||
},
|
||||
})
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
let has_impl_trait = |def_id| {
|
||||
iter::successors(Some(tcx.generics_of(def_id)), |generics| {
|
||||
generics.parent.map(|def_id| tcx.generics_of(def_id))
|
||||
})
|
||||
.any(|generics| generics.has_impl_trait())
|
||||
};
|
||||
if let ExprKind::MethodCall(path, args, span) = expr.kind
|
||||
&& let Some(typeck_results) = self.infcx.in_progress_typeck_results
|
||||
&& let Some(substs) = typeck_results.borrow().node_substs_opt(expr.hir_id)
|
||||
&& substs.iter().any(|arg| self.generic_arg_contains_target(arg))
|
||||
&& let Some(def_id) = typeck_results.borrow().type_dependent_def_id(expr.hir_id)
|
||||
&& self.infcx.tcx.trait_of_item(def_id).is_some()
|
||||
&& !has_impl_trait(def_id)
|
||||
{
|
||||
let successor =
|
||||
args.get(1).map_or_else(|| (")", span.hi()), |arg| (", ", arg.span.lo()));
|
||||
let substs = self.infcx.resolve_vars_if_possible(substs);
|
||||
self.update_infer_source(InferSource {
|
||||
span: path.ident.span,
|
||||
kind: InferSourceKind::FullyQualifiedMethodCall {
|
||||
receiver: args.first().unwrap(),
|
||||
successor,
|
||||
substs,
|
||||
def_id,
|
||||
}
|
||||
})
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
|
|||
|
|
@ -22,6 +22,7 @@
|
|||
#![feature(let_else)]
|
||||
#![feature(min_specialization)]
|
||||
#![feature(never_type)]
|
||||
#![feature(try_blocks)]
|
||||
#![recursion_limit = "512"] // For rustdoc
|
||||
|
||||
#[macro_use]
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue